Compression of the median nerve by an anomalous palmaris longus tendon: a case report.

A report on compression of the median nerve in distal forearm and wrist by an accessory muscle (the palmaris bitendinous) is described. Its position, deep to the palmaris longus, and distal insertion on the deep surface of the superficial aponeurosis were similar to palmaris profundus. Nevertheless, both its tendinous-musculo-tendinous structure and the origin from the dorsal epimysium of the palmaris longus muscle belly were unlike palmaris profundus.